/*
 * Copyright (c) 2002-2010 Atsuhiko Yamanaka, JCraft,Inc.  All rights reserved.
 * Copyright (c) 2010-2011 Michael Laudati, N1 Concepts LLC.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3. The names of the authors may not be used to endorse or promote products
 * derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JCRAFT,
 * INC. OR ANY CONTRIBUTORS TO THIS SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.vngx.jsch.userauth;

import org.vngx.jsch.Session;
import org.vngx.jsch.exception.JSchException;

/**
 * Implementation of <code>UserAuth</code> for "none" authentication.
 *
 * A client may request a list of authentication 'method name' values that may
 * continue by using the "none" authentication 'method name'.
 *
 * If no authentication is needed for the user, the server MUST return
 * SSH_MSG_USERAUTH_SUCCESS.  Otherwise, the server MUST return
 * SSH_MSG_USERAUTH_FAILURE and MAY return with it a list of methods that may
 * continue in its 'authentications that can continue' value.
 *
 * This 'method name' MUST NOT be listed as supported by the server.
 *
 * @author Atsuhiko Yamanaka
 * @author Michael Laudati
 */
public final class UserAuthNone extends UserAuth {

	@Override
	protected boolean authUser(Session session, byte[] password) throws Exception {
		super.authUser(session, password);

		// send user name for "none" auth request
		// byte      SSH_MSG_USERAUTH_REQUEST(50)
		// string    user name
		// string    service name ("ssh-connection")
		// string    "none"
		_packet.reset();
		_buffer.putByte(SSH_MSG_USERAUTH_REQUEST);
		_buffer.putString(session.getUserName());
		_buffer.putString(SSH_CONNECTION);
		_buffer.putString(UserAuth.NONE);
		session.write(_packet);

		while( true ) {
			switch( session.read(_buffer).getCommand() & 0xff ) {
				case SSH_MSG_USERAUTH_SUCCESS:
					return true;		// In case server allows 'none' user auth access!

				case SSH_MSG_USERAUTH_BANNER:
					userAuthBanner();	// Process banner message and continue
					break;

				case SSH_MSG_USERAUTH_FAILURE:
					userAuthFailure();	// Receive methods which can continue
					return false;

				default:
					throw new JSchException("Invalid UserAuth 'none' response: " + _buffer.getCommand());
			}
		}
	}

}
